Canola and olive oils compared with sunflower oil in women with PCOS
What it found
In women with polycystic ovary syndrome, canola oil improved cholesterol and triglyceride measures and both canola and olive oils reduced fatty liver grade, while sunflower oil did not.
The trial ran for 10 weeks in 72 women.
What they found
Studies in people
Blood fats with canola
In the canola oil group, triglycerides, non-HDL cholesterol, and the ratios TC/HDL, LDL/HDL and TG/HDL all fell significantly over the 10 weeks. Total cholesterol and LDL cholesterol showed a marginal drop.
Blood fats with olive
Olive oil did not significantly change any blood fat measure over the 10 weeks.
Blood fats with sunflower
Sunflower oil produced no significant changes in blood fats or fatty liver grade.
Insulin resistance
HOMA-IR, a measure of insulin resistance, fell significantly in both the canola and olive oil groups. The fall was larger with canola oil (0.81) than with olive oil (0.57).
Fatty liver grade
Fatty liver grade fell significantly in the canola and olive oil groups, with no significant difference between them. There was no change in the sunflower oil group.
SHBG levels
SHBG, a hormone-binding protein, did not change significantly in any of the three groups.
What the authors conclude
“Canola oil, as a good source of MUFA and ALA, showed beneficial effects on lipid profile compared to olive, and sunflower oils in women with PCOS.”
Also in their conclusions
- They conclude that canola oil, as a good source of monounsaturated fat and alpha-linolenic acid, showed beneficial effects on lipid profile compared to olive and sunflower oils in women with PCOS.
- They say that substituting canola or olive oils for sunflower oil could attenuate fatty liver status in women with PCOS.
- They call for more studies to determine the proper amounts of these oils to achieve the best results.
How it was done
Sunflower oil is one of the most common and cheapest cooking oils, and the authors wanted to see how it compares with canola and olive oils for blood fats and liver fat in women with PCOS.
They randomly assigned 72 women with PCOS, aged 18 to 45, to eat 25 g a day of canola, olive, or sunflower oil for 10 weeks. Blood tests and liver ultrasound were done at the start and end.
What it can’t tell you
- This trial lasted only 10 weeks, so it cannot show what happens over longer periods.
- The women all had PCOS, so the results may not apply to other groups.
- Fatty liver was assessed by ultrasound, which is not very accurate for mild cases.
Who paid
- Conflicts
- The authors declare that they have no competing interests.
- Authors work at
- Isfahan University of Medical Sciences, Iran
The paper
- Title
- The effects of canola and olive oils consumption compared to sunflower oil, on lipid profile and hepatic steatosis in women with polycystic ovarian syndrome: a randomized controlled trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Yahay M, Heidari Z, Allameh Z, Amani R (2021). The effects of canola and olive oils consumption compared to sunflower oil, on lipid profile and hepatic steatosis in women with polycystic ovarian syndrome: a randomized controlled trial. Lipids in health and disease. doi:10.1186/s12944-021-01433-9Free full textPubMed 33514384DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error